1. Field of the Invention
This invention relates to the preparation of isopropenyl esters of dicarboxylic acids and more particularly to the synthesis of isopropenyl esters of saturated and unsaturated aliphatic and aromatic dicarboxylic acids and also to the synthesis of the half isopropenyl ester-half carboxylic acid products from the same dicarboxylic acids.
2. Description of the Prior Art
Isopropenyl esters of dicarboxylic acids are not new; they have been prepared previously as described in British patent 1,037,897 and in J. Org. Chem., 31, 629, 1966. However, the processes described by both of these references use toxic and poisonous catalysts such as boron trifluoride and mercury salts.
Compounds such as our half isopropenyl ester-half carboxylic acid compounds have not, to our knowledge, been reported as the major products of a reaction, but only as minor co-products in the preparation of diisopropenyl esters.